1. Field of the Invention
The present invention generally relates to the application of a laser beam to the remote drawing of an image, such as a picture, characters and various patterns, using its properties of directivity, high intensity and monochromaticity, by scanning the laser beam by means of an optical scanner such as the galvanometer scanner, and particularly to a method of and system for drawing an image over a background or more specifically for drawing pictures of constellations having a background of stars in the sky.
2. Description of the Related Art
Recently, in the fields of education, culture, lifestyle etc., activities reflecting harmony with nature have become necessary so that a better understanding of the cosmos and heavenly bodies is promoted by directly communing with nature. In this connection, enrichment of facilities for such a purpose has come to be needed in various fields. In this context, constellation classes or meetings for observing stars in the sky have been planned and held at a lot of places.
Incidentally, when explaining a constellation and its constituent stars, which is often needed in the classes or meetings, it is quite difficult to have the participants imagine the picture of the constellation, to which the explanation is directed, with respect to the actual stars which they are watching.
As a prior art approach to this, there is proposed a constellation image display apparatus disclosed in Japanese patent application laid-open (KOKAI) No. 4-134480, which enables an easy comparison of an actual constellation with its associated image by using a combiner. The combiner includes a half-mirror not only to pass the light from the starlit sky but also to reflect a constellation image created on a cathode ray tube (CRT) display such that they can be observed in a superimposed fashion with each other.
This prior art system is, however, for personal use, and is not appropriate for simultaneous observation by a lot of people. At present, there is no effective means usable for an explanation of stars and constellations to a lot of people with reference to the actual stars in the sky.